[MUD-Dev] Modeling spells/skills as collections of affects

[Travis Casey]

Brian Price <blprice at bedford.net> wrote:
> 
> In the codebases I've seen thus far, spells and skills are largely
> hardcoded.  I would like to implement a system where they were instead
> parameterized and stored in the mud's database.  One approach to this
> would be to describe spells and skills as a collection of
> event-dependant affects.  To implement this, the definition of affects
> would need to be expanded a bit, for example, a mud object's location
> would be an affectable state.  Also, there would need to be a system
> of events which would trigger the various affects.  
> 
> Has such a system been implemented elsewhere?  If not, any thoughts on
> how such a system could/should be implemented?

I haven't seen in implemented on a mud anywhere, although it is one of
my planned projects, if I ever get around to doing my fantasy mud idea.
However, there have been several pencil-and-paper RPGs which have done
it, with varying degrees of success:

Hero system, which Jeff Kesselman already mentioned.  The Hero system
uses a number of pre-defined powers which can be bought in varying 
levels.  There are also a variety of advantages and limitations which 
can be applied to the powers.  Characters spend points to buy powers.
The system is also applicable to creating super powers, magic items,
or any other kind of special power.  Since it's meant ot be usable in 
any sort of game world, it provides no "flavor" on its own; it's up
to the GM to provide that.

Torg has a magic system in which spells can be designed by choosing
how they work, how long they take to cast, how long their effects last,
etc.  There is no pre-defined list of effects; rather, the spell designer
chooses an effect, and the system gives guidelines for determining the
difficulty of a spell which would produce that effect.  The end result
of the system is a difficulty factor, which is used in a skill check
to determine whether the mage can successfully cast the spell.

Fantasy Wargaming has a system which allows for creation of spells
with difficulty factors, in concept much like Torg's, but very different
in detail.  Again, the end result is a difficulty factor.

Both of these systems have a *lot* of flavor built in -- the way that
magic works in those particular worlds is built-in to the spell creation
process, so any spell generated with these systems will "fit" in those
worlds.

The Grimoire, a supplement for Shadowrun, also has a spell creation 
system.  In this case, the end result is a drain factor indicating how
much casting the spell drains the mage.  It has more flavor than Hero's
system, but less than Shadowrun or Torg.

All these systems are alike in that they're mainly concerned with
the *effects* of the spell, and not the *process* of the spell.  The
Mage2Mage system, available on the Internet, treats spells as being
like computer programs -- a mage "writes" a spell, giving it a series
of things to do.  Conditional statements, loops, interrupts, and other
such things are possible.  IMHO, this could make an incredibly good
magic system for a mud.  I should note, though, that Mage2Mage doesn't
seem to have ever been completed -- the only versions I've found on
the 'net are 0.86 and 0.88.  You can get it through an email server
at:

http://www.hookup.net/~gschmidt/sams/list.rpg.html

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